If the camcorder supports USB it is only for low res video or still pictures. You won't get full DV resolution video. You need a firewire card for your PC. Be sure to get one with a Texas Instruments (TI) chip.

They are clearly labeled with the Displayport logo. Your computer (like most these days) can be connected to two or three monitors. You're probably only using one. Those ports have nothing to do with Firewire.

Many people us multiple monitors. Sometimes one is connected to a big screen TV for watching movies. Stock traders like to have several monitors to watch more stocks. Developers like to have one monitor to run the Develpement software, another to run the program they're building/debugging. Sometimes just to have more Desktop space (more programs running and visible at once).

Even if you only use one monitor several types of connectors have been used over the years: VGA (oldest), DVI, HDMI, Displayport (newest).

That's an HDMI port on the other computer. Another monitor port. You cannot connect your firewire camcorder to that.

Firewire ports were never common on Windows PCs. And they have pretty much disappeared from them in the last 10+ years.

Firewire: for cameras/camcorders, and older pro-audio equipment, also for harddrives/storage
looks like this - [Attachment 49807 - Click to enlarge]
(computer usually has full size 6pin, but some, including laptops, have the mini 4pin version, almost ALL cameras that use it have the mini 4pin. they ARE compatible - the extra 2 pins are supposed to be for distributing power)

Again, you need to get an add-on Firewire card. Easy to find, used or new. Just make sure it has TxInstruments chipset, as mentioned.

I think it might just be easier to take a trip down to a shop and let them do the copying of the tapes

4 tapes with about 30 minutes on each

For four tapes, definitely. Make sure they capture via firewire and deliver DV in .AVI (best for Windows) or .MOV (best for Mac). That gets you an exact copy of what's on the tape. If they capture with an analog capture device you will get lesser quality.

No, you want them as DV AVI. That is an exact copy of the digital data on the tape. It's higher quality than converting to MPEG and more easily edited (and without further degradation). Once you're done editing you can convert to MPEG if necessary (for DVD, for example).